Control apparatus



. K. A. SIMMON.

CONTROL APPARATUS.

APPLICATION HLED 0150.13, 1919.

1,389, 1 O5 Pateflted Aug. 3%, W210.

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wnuzssss: INVENTOR 7 Karl A 51722122012 W ATTORNEY UNITED STATES PATENT OFFIC.

, KARL A. SIMMON, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING HOUSE ELECTRIC 8a MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VAN 1A.

CONTROL APPARATUS.

Patented Aug. 30, 1921.

Application filed December 13, 1919. Serial No. 344,745.

To all whom it may concern:

Be it known that I, KARL A. SIMMON, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Apparatus, of which the following is a specification.

My invention relates to control apparatus and it has special relation to manually operated, rotative-type controllers.

The object of my invention is to provide a relatively simple and reliable controller of the type indicated which shall embody a spirally arranged resistor or conducting member together with a contact arm that is operated by the controller handle to vary the active portion of the resistor.

Another object of my invention is to render a controller of the class in question substantially explosion-proof by immersing the resistor and contact arm in non-inflammable liquid and providing a natural circulation thereof through the controller.

Other objects of my invention will become evident from the following detailed description taken in conjunction with the accompanying drawing, wherein- Figure 1 is a view,in longitudinal section, of a control apparatus constructed in accordance with my present invention; and

Fig. 2 is a transverse sectional view taken along the line IL-II of Fig. 1.

Referring to the drawing, the structure here shown comprises a tank or containing case 1, which is provided with a side opening 2 near its upper end and a bottom opening 3 and is inclosed on its top side by a cover or plate 4 that is provided with a centrally located apertured boss 5 through which an operating shaft 6, preferably of hard insulating material, extends. The outer end of the shaft 6 is rigidly secured to a suitable operating handle 7, while the lower end of the shaft is journaled at 8 upon the bottom wall of the tank or case 1. I

A radiator or cooling member 9, which maybe corrugated, if desired, is provided with a plurality of hollow arms that are bolted to the tank 1 to effect fluid-tight communication between the tank and. the raditially filled with a non-inflammable cooling medium, such as carbon tetrachlorid, and, during operation of the controller, a natural circulation of liquid is maintained in the direction of the arrows, namely, upwardly through the controller case 1, outwardly through the side opening 2 to the radiator 9, downwardly through the radiator and thence through the bottom opening 3 to the tank 1. 1

Insulating brackets or supports 15'and 16 are secured to one side wall of the controller near the bottom and the top ends thereof,

thermore, the resistor may be made of a wire wound around an insulated bar or pipe.

A contact arm 18 has a sliding fit with the operating shaft 6 and is secured, by a metallic key 19, to the shaft to insure rotative movement of the contact arm in accordance with the actuation of the controller handle 7. In this way, the contact arm 18 is free to slide longitudinally along the shaft. 6 but is locked against rotative movement relative thereto.

The outer end 20 of the contact arm 19 is bifurcated, the horizontally-extending arms respectively passing over and under the spiral conducting strip or resistor 17. In this way, the contact arm is properly guided to maintain good electrical contact between the spiral resistor 17 and a spring clip or 'finger 21 that is electrically attached to the member 20.

For the purpose of leading current into or away from the contact arm 18, a collector or slip-ring 22 is secured to the operatingshaft 6 to make electrical connection with the contact arm 18 through'the key 19, or otherwise. A brush or control finger 23 bears upon the slip-ring 22, is insulatedly secured to the top cover 4 by a bracket 24 and is connected to the external electrical circuit by means of an insulated conductor or cable 25 which extends through the cover plate 4..

' bracket 16, An insulated conductor or cable 27 extends from the socket; 26'through the side wall of the tank 1 to the'desired external circuit.

The operation of the illustrated apparatus may be set forthas follows. Initially, the contact arm 18 occupies its lowest possible position, wherein the contact clip 21 engages the lower end of the spiral resistor 17. It will be understood that the parts are properly insulated to prevent grounding on the controller case 1. Under such conditions, the electrical circuit of the controller is established from the conductor 25 through control finger 23, slip-ring 22, key 19, conrally-arranged reslstor, and a contact arm I operating inside of said resistor and adapttact arm 18, spiral resistor 17 and socket to the conductor 27'; Consequently, I the maximum resistance value is provided by the controller, since all of the spiral reslstor 17 is'included in circuit.

By rotating the operating handle 7 in a counter-clockwise direction, when viewed from above, the contact arm 18 rotates with the operating shaft 6 but gradually slides upwardly along the shaft-by reason of the guiding effect of 'th'e'bifurcated end 20 to fthe contact arm. In this way, the active portion of the spiral resistor 17 is gradually diminished, to correspondingly reduce the resistance value of the control device, until a the upper 'end of the spiral resistor is reached, which limiting position is" determined by the engagement of the contact arm'18 and the supporting bracket 16. Under such conditions, the resistance value of the control apparatus is substantially zero.

During the controller operation, the previously mentioned natural circulation of liquid through the controller occurs as the resistor and other conducting elements are heated by the current traversing them, and not only is a dangerous operating temperature prevented in'this manner, but the noiiinflammable properties of the carbon tetrachlorid or other suitable liquid 11 absolutely prevent the formation of eluding any possibility of controller exp'losions. I

i It will 'be appreciated that, if desired, the operating handle 7 may be geared to the operating shaft 6 to reduce the necessa movement of the handle 7 to effect the" travel of the contact arm 18 from the one to theother endof the spiral resistor 17. l I do not wishto be restricted to the specarried thereby to enga snarks, thus pre- 1 pended claims.

TcIa im as my invention:

1.'Control apparatus comprising a spirally-arranged self-supporting resistor and means for varying the active portion thereof.

2. Control apparatus comprising a spirally-extending conducting member and means adapted to follow the contour of sald member for varying the resistance thereof. 3. Control apparatus comprising a spirally-disposed conductor, means for varying the active portion thereof, and means for causing a cooling liquid to traverse sald conductor. h

4. Control apparatus comprising a spied to follow-the contour thereofi,

5. Control apparatus comprising a spirally-arranged resistor, an operating j shaft extending therethrough, and ;a contact arm said resistor and adapted to slide longitudinally on said shaft.

6. Control apparatus comprising" aspirally-arranged resistor, an operating shaft extending therethrough, a contact arm' carried thereby to engage said resistor and adapted to slide along said shaft, and means for immersing said resistor.

7. Control apparatus comprising a spi rallyarranged resistor, an operating shaft extending therethrough,'a,'contact arm carried thereby to engage said resistor and adapted to slide along said shaft, and means for causing a circulation of cooling medium throu h said controller. 8. Control apparatus comprising a tank containing a s irally-arranged reslstor and a contact arm or varying theactive portion thereof, and a cooling member externally communicating with the bottom and the top of said tank.

- 9. Control apparatus comprising a spirally-arranged resistor, an operating shaft extending therethrough,'a contact arm carried thereby to engage said resistor and adapted to slide along said shaft, a radiatorkexternally communicating with said tan I In testimony whereof I. have hereunto subscribed my name this 8th day of December, 1919, g

KARL A. SIMMON, 

